The collection for People Tree is aimed at bringing fair trade and organic fashion to the 16-24 age group. Watson is acting as creative advisor, injecting her personal style into the range.

"I was excited by the idea of using fashion as a tool to alleviate poverty and knew it was something I could help make a difference with," she said.

"I think young people like me are becoming increasingly aware of the humanitarian and environmental issues surrounding fast fashion and want to make good choices but there aren't many options out there."

The People Tree line, comprising 26 women's styles and 15 for men, plus a small accessories range, will enter stores in late February 2010. The collection, which includes knitwear, cotton T-shirts, jersey dresses, poplin skirts and shorts, is described by People Tree as "clean, sexy and easy to wear".

Much of the range uses organic and fairly traded cotton. The clothes are made entirely by hand by fair trade groups using weaving, knitting and embroidery, helping to create livelihoods for disadvantaged groups in Bangladesh, India and Nepal.

• The collection will be available at People Tree concessions and online. For more details, visit peopletree.co.uk.